title: Supramolecular Structures of Enzyme Clusters.
abstract: The structural characterization of subtilisin mesoscale clusters, which were previously shown to induce supramolecular order in biocatalytic self-assembly of Fmoc-dipeptides, was carried out by synchrotron small-angle X-ray, dynamic, and static light scattering measurements. Subtilisin molecules self-assemble to form supramolecular structures in phosphate buffer solutions. Structural arrangement of subtilisin clusters at 55 °C was found to vary systematically with increasing enzyme concentration. Static light scattering measurements showed the cluster structure to be consistent with a fractal-like arrangement, with fractal dimension varying from 1.8 to 2.6 with increasing concentration for low to moderate enzyme concentrations. This was followed by a structural transition around the enzyme concentration of 0.5 mg mL-1to more compact structures with significantly slower relaxation dynamics, as evidenced by dynamic light scattering measurements. These concentration-dependent supramolecular enzyme clusters provide tunable templates for biocatalytic self-assembly.
authors.affiliation: WestCHEM, Department of Pure & Applied Chemistry and Department of Chemical and Process Engineering, University of Strathclyde , Glasgow G1 1XJ, United Kingdom ; WestCHEM, Department of Pure & Applied Chemistry and Department of Chemical and Process Engineering, University of Strathclyde , Glasgow G1 1XJ, United Kingdom.
authors.forename: Nadeem
authors.initials: N
authors.lastname: Javid
authors.forename: Karsten
authors.initials: K
authors.lastname: Vogtt
authors.forename: Sangita
authors.initials: S
authors.lastname: Roy
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Hirst
authors.forename: Armin
authors.initials: A
authors.lastname: Hoell
authors.forename: Ian W
authors.initials: IW
authors.lastname: Hamley
authors.forename: Rein V
authors.initials: RV
authors.lastname: Ulijn
authors.forename: Jan
authors.initials: J
authors.lastname: Sefcik